Cell biology

Cell is the basic structural and functional unit of life. Study of a cell and its various properties is known as cell biology or cytology. It includes study of cell’s structure, function, division, interactions with different cells and death. Its study allows a deeper understanding of the organelles and other entities present within the cell. It also allows integration of molecular knowledge to the cellular milieu and the formation of tissues, organs and organism. It can be done at both micro and molecular levels. It encompasses the diverse life forms ranging from single celled bacterium to multicellular organisms like mammals, plants, etc. The history of research in the field of cell biology dates back to 1665’s. Initial observation of Robert hooke in 1665 of plant cell walls in a slice of cork marked a significant step towards the discovery of moving cells by Antonie van Leeuwenhoek. Later, in 1830’s two scientists named Schleiden a botanist, and Schwann, a zoologist gave the cell theory as per which cell is the fundamental unit of life.

As microscopic techniques advanced with time during nineteenth and twentieth centuries our knowledge about cell also improved. Advanced staining methods and sectioning techniques enabled vision of more internal details of the cell, thus also increasing curiosity about further depth of their functioning. Several questions like how cells produce energy, how different cells specialize in different functions, how do cells divide and how they die, were answered gradually during the 20^th century. Cell biology or study of cell also developed into a vast field with several subfields emerging like genetics, molecular biology, developmental biology, ecology, evolution and recently added interdisciplinary study called systems biology. Cell communication, transport and signaling is also a major part of cell biology research.

Various cellular processes that are studies as a part of cell biology are:

1. Metabolism: includes study of various metabolic pathways occurring within the cell like glycolysis, krebs cycle, respiration, photosynthesis, etc.
2. Signaling and transport: cell-cell signaling of various chemicals and organic/inorganic molecules
3. Cell reproduction or cell division: mitosis, meiosis, fragmentation, budding, embryology, developmental sciences,
4. Cell death: apoptosis, autophagy, necrosis, etc
5. Cell movement: flagella, cilia, chemotaxis, phototaxis, contraction, relaxation, neuronal depolarization, etc.
6. Cell origin – ecology and evolution
7. Protein and gene expression studies
8. Sub cellular compartments like golgi, mitochondria, cytoskeleton, cell membrane, cell wall, ribosomes, endoplasmis reticulum, vesicles, nucleus, etc.

These studies are possible only because of various advanced techniques like:

1. Invitro cell culture: maintainence of animal, plant or bacterial cells under artificial conditions mimicking the in vivo milieu
2. DNA microarrays
3. Flow cytometry
4. PCR
5. Microscopy
6. Chromatography
7. Gene knockdown
8. Transfection studies
9. Cell fractionation
10. Cellular immunoprecipitation, etc